Species-specific acoustic behavior will be studied from the point of view of auditory neurophysiology and behavior genetics. It is possible to hybridize two species of Teleogryllus to obtain F-1 and backcross hybrids. In addition, it is possible to make parthenogenic clones of homozygous individuals from Teleogryllus. Such clones will be used to investigate the genetic control of acoustic behavior and also the details of the neural networks that underlie acoustic behavior. It is likely that the temporal pattern of the call is influenced by sex-linked factors that may reside on the X-chromosome, a possibility that we will explore by genetic, behavioral, and physiological analyses. We propose that a common set of genes controls species-specific acoustic behavior in both males and females, possibly by influencing that part of the CNS that generates the species-specific temporal pattern, the song oscillator. While much is known about song production, little is known about how neural circuits in the auditory pathway achieve species-specific $ sensitivity. A search for neural correlates of song selectivity in Teleogryllus and its hybrids will be made. Our goal is to find (1) neural filters that are selective to particular features of the call rhythm, and (2) to determine how the properties of these units are altered in hybrids (or in homozygous clones), and thus to identify neural elements that are subject to genetic control. Finally, by employing song synthesis technique, to observe the effect of altered song upon behavioral responsiveness, an attempt will be made to identify the particular aspects of the temporal pattern that confers upon it species-specificity. Presumably it is precisely these parameters of the signal that are under direct genetic control, and are also the elements of the signal for which the auditory neurons in the species-filter are especially responsive.